The present invention relates to plumbing fixtures, and more particularly, to fill valves that automatically re-fill the tank of a gravity operated flush toilet.
A conventional gravity operated flush toilet has several basic components. The china components include a porcelain bowl and a porcelain tank mounted on top of the bowl. The bowl and tank may either be separate pieces or may be molded as a single unitary piece of china. The plumbing components of a conventional gravity operated flush toilet include a fill valve in the tank that is connected to a water supply line, a flush valve mounted in a hole in the bottom wall of the tank that communicates with the bowl, a flapper valve that normally closes the flush valve, and a lever or push button on the outer wall of the tank that is connected with a chain or other mechanical linkage for momentarily lifting the flapper valve. This allows water stored in the tank to flow rapidly through the flush valve into the bowl to carry waste along with the water through a trap connected to the underside of the bowl and into a waste pipe connected to a sewer line, septic tank or other waste reservoir.
For many years ballcock fill valves have been utilized in toilet tanks. They are noisy, require much space to operate, and must be adjusted upon installation based on the supply line water pressure in order to ensure proper shut off. Their most annoying attribute is that they tend to run on and make a hissing noise for a long duration as the float arm gradually shuts off the flow of water into the toilet tank. Almost everyone at one time or another has had the experience of lifting the toilet tank lid and bending the metal float arm in the hopes of achieving a proper shut off Pilot operated toilet tank fill valves have been developed which are quieter, require less space, are more durable and have positive, rapid shut off. One example is the Model 528 fill valve sold under the HUNTER trademark by Hunter Plumbing Products of San Marcos, Calif. The Model 528 HUNTER fill valve embodies the invention disclosed in U.S. Pat. No. 5,715,859 of David Nichols-Roy granted Feb. 10, 1998.
In the United States there are two basic markets for toilet tank fill valves, namely, the original equipment manufacturer (OEM) market and the after-installation market. The former consists of large toilet manufacturers such as American Standard and Kohler who assemble and sell complete gravity operated flush toilets including fill valves. The latter consists of hardware and plumbing supply stores that sell to plumbers and home owners for repair and replacement in toilets already installed in residences.
Every gravity operated flush toilet has an optimum fill level which ensures that enough water is in the tank for proper flushing without wasting water or risking incomplete waste carry out. For many years gravity operated flush toilets in the United States had tanks with capacities of three and one-half, five gallons or more. In recent years, the Environmental Protection Agency (EPA) has mandated that low water consumption toilets be installed in all new construction and during all re-models, with a maximum water usage of 1.6 gallons per flush. Both the older high volume gravity operated flush toilets and the newer low volume gravity operated flush toilets come in a wide range of tank configurations with different optimum fill levels. Because of this, the Model 528 HUNTER fill valve has been manufactured with a telescoping riser so that the main body of the fill valve that contains the pilot operated diaphragm valve and the float arm can be set for the predetermined height that will ensure that the tank refills to the optimum level. The Model 528 HUNTER fill valve is advantageously sold into the after-installation market since it permits plumbers and do-it-yourself homeowners to install the fill valve and rapidly adjust its height as necessary. However, the OEM market requires no such adjustability. The telescoping members and locking devices used in some fill valves to fix their positions represent unneeded material and complexity for the OEM market. However, it would be unduly expensive to manufacture a variety of different fill valves having different fixed heights to satisfy the configurations of the various gravity operated flush toilets manufactured in the United States and abroad.